Experimental Investigation on Seismic Performance of the Masonry Structure with Reinforced Concrete Walls and Large Openings at Its Bottom Floor

In view of the key problems such as the weakened seismic performance and reduced safety caused by the expansion of openings at bottom floor of masonry structure to meet the functional requirements, a 1:4 scale model of a four-story brick-concrete masonry structure was designed and fabricated. Based on the principle of stiffness equivalence, the partial masonry walls on the side of the bottom floor with large openings were replaced by reinforced concrete walls, and then the pseudo static test was conducted on the model. Through the test, the seismic performance indexes such as the failure mode of each floor, the displacement, hysteresis curve, skeleton curve, and stiffness degradation were obtained. The results showed that the masonry structure can form a close connection with the reinforced concrete walls and then the whole structure exhibits the characteristic of ductility. There is no sudden change in bearing capacity during the loading and the hysteresis curves show that the structure retained a certain energy dissipation capacity during cyclic loading, without sudden loss of bearing capacity. The displacement of the second floor of the structure changes significantly, and its stiffness should thus be paid more attention to during the design process to avoid the formation of a weak floor. The torsional of the masonry structure with large openings at its bottom floor under earthquake can be avoided through the setting of reinforced concrete walls.